Archived

Avalanche Forecast

Feb 24th, 2018–Feb 25th, 2018

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: South Coast.

Lots to think about: 1) Storm slabs have formed on all aspects, 2) Strong winds have loaded lee features, 3) Expect touchy cornices on ridges. Be cautious and conservative with your decision making and stick to low-angled, sheltered terrain.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

SATURDAY NIGHT: Cloudy with snowfall, accumulation 15 to 25 cm, strong westerly winds, treeline temperature -4 C, freezing level 500 m.SUNDAY: Mostly cloudy with possible convective flurries and lightning and afternoon sunny skies, light to moderate westerly winds, treeline temperature -7 C, freezing level 400 m.MONDAY: Mostly cloudy, light northwesterly winds, treeline temperature -5 C, freezing level 500 m.TUESDAY: Cloudy with light snowfall, accumulation 5 to 10 cm, moderate westerly winds, treeline temperature -4 C, freezing level 600 m.

Avalanche Summary

The new snow was reactive to skier activity on Friday, producing small (size 1) dry loose and storm slabs.Expect natural and human-triggered avalanche activity to increase with the incoming storm followed by warming sunshine.

Snowpack Summary

Around 30 to 40 cm of storm snow fell on Friday and another 25 cm of snow is forecasted for Saturday night, with more possible with convective flurries on Sunday. Both of these storms had strong southerly winds. Expect touchy storm slabs on all aspects with deeper deposits found in lee features. All of this snow fell on previously wind-affected surfaces and a sun crust on southerly aspects. The new snow may not bond well to these surfaces and could be reactive to both natural and human triggers.A hard rain crust that extends into alpine terrain is buried about 60 to 100 cm. Reports suggest the snow has a poor bond to the crust with test results showing sudden planar characteristics and a Rutschblock 2 (the whole block failing after standing on it). Monitor the bonds of the new snow as well as the bond of the snow directly above the buried crust. There are no substantial layers of concern below the crust.Also make note of cornices at ridgeline. Variable winds in the past month have produced cornices on all aspects. They will become touchier as they grow in size, as temperatures rise, and as the sun packs a strong punch on clear days. Stand well back of them!

Avalanche Problems

Storm Slabs

Storm slabs have formed with new snow and strong winds. They sit above previous wind slabs that are not bonding well to a buried crust. Expect human and natural avalanche activity. Stick to low-angled terrain and give the snow time to stabilize.

Use ridges or ribs to avoid pockets of wind-loaded snow.Watch for signs of instability, such as avalanche activity, whumpfs, and shooting cracks.Use caution above cliffs and terrain traps where small avalanches may have severe consequences.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 2.5